The present invention relates to a device for preventing scattering of particles, suitable for use in color sorting apparatus for sorting particles according to their colors.
Such a color sorting apparatus has been known as having a particle chute in which particles flow down, particle supplying means for supplying particles to the upper end of the chute, and a photoelectric sorting chamber disposed at the lower end of the chute, the photoelectric sorting chamber accommodating a photo-electric sorting device including a photoelectric detector having a light source and a light-receiving element disposed around the path of flow of the particles from the chute and a blowing nozzle device adapted to operate in response to the output from the light-receiving element of the photoelectric detector.
In this known sorting apparatus, fine powders and dusts attaching to the sorted particles are blown by the air from the blowing nozzle device and are scattered and diffused to fill the photoelectric sorting chamber. These powders and dusts suspended in the air then attach the transparent surfaces of the light source and light-receiving element of the photo-electric detector. In addition, the sorted particles are scattered to intermittently interrupt the transmitted or reflected light to be received by the light-receiving element. In consequence, the amount of light coming from the light source of the photoelectric detector is attenuated and the detection sensitivity of the light-receiving element is lowered resulting in erroneous sorting operation and, hence, deterioration in the sorting performance of the apparatus.